Interpretation of gravity data derived from the Earth Gravitational Model EGM2008 in the Center-North Cameroon: structural and mining implications

Abstract

This work presents an interpretation of gravity data derived from the Earth Gravitational Model EGM2008 in the Center north Cameroon and a correlation with previous tectonic geological and mining studies. EGM2008 Model provides high spatial resolution gravitational data integrating land, airborne, maritime gravity data, as well as satellite altimetry data. Significant similarities are underlined through Bouguer anomaly maps deduced from EGM2008 and land gravity data according to shape, orientation, and amplitude of anomalies. Furthermore, the statistical analysis of both datasets gives means of −38.25 and −38.21 mGal as well as standard deviations of 12.30 and 12.42 for EGM2008 and land data, respectively. Regional geological formations are largely interpreted and identified on EGM2008 Bouguer anomaly map. We applied regional/residual separation filtering, upward continuation and horizontal gradient methods to investigate the subsurface structure. Some known geological lineaments are highlighted such as Poli and Koum faults and Tchollire shear zone, while new ones are revealed. This work brings out main regional feature known as Poli-Ounianga-Kebir gravity heavy line trending SW-NE which contains uraniferous and auriferous deposits located along the same direction. This paper presents a coherent correlation between positive gravity anomalies, faults, and mineral indices in the Center-North Cameroon (Central Africa Fold belt), and thus brings new evidences of the efficiency of Earth Gravitational Model EGM2008 for structural investigation and mining exploration.